NSTextView wrapper for SwiftUI

RichTextEditor.swift

//
//  RichTextEditor.swift
//  SwitDataApp
//
//  Created by zentrope on 1/17/22.
//

import AppKit
import Combine
import SwiftUI

struct RichTextEditor: NSViewRepresentable {
    
    @Binding var attributedText: NSAttributedString
    @Environment(\.showRuler) private var showRuler: Bool
    @Environment(\.defaultFontSize) private var fontaize: Double
    @Environment(\.showInspector) private var showInspector: Bool
    // MARK: - defaultScale not working as expected
    // @Environment(\.defaultScale) private var magnification: Double
    @Environment(\.findBarPosition) private var findBarPosition: NSScrollView.FindBarPosition

    var activity: PassthroughSubject<Date, Never>

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    func makeNSView(context: Context) -> NSScrollView {
        let scrollview = NSTextView.scrollableTextView()

        // MARK: - NSScrollView Settings
        // Here you can specify settings for NSScrollView
        scrollview.drawsBackground = true
        scrollview.borderType = .noBorder
        scrollview.hasVerticalRuler = true
        scrollview.hasHorizontalRuler = true
        scrollview.autoresizingMask = .width
        // MARK: - defaultScale not working as expected
        scrollview.allowsMagnification = true
        scrollview.allowedTouchTypes = .indirect
        scrollview.findBarPosition = findBarPosition
        scrollview.horizontalScrollElasticity = .automatic
        scrollview.automaticallyAdjustsContentInsets = true
        scrollview.translatesAutoresizingMaskIntoConstraints = true
        // MARK: - ⚠️ CAUTION: DO NOT DARE TO ENABLE/UNCOMMENT OR UNLEASH THE APOCALYPSE ⚠️
        // scrollview.hasVerticalScroller = true
        // scrollview.hasHorizontalScroller = true
        // scrollview.scrollerStyle = .legacy
        // scrollview.autohidesScrollers = true
        // scrollview.scrollerKnobStyle = .light

        // MARK: - NSTextView Settings
        // Here you can specify settings for NSTextView
        let textview = scrollview.documentView as! NSTextView
        textview.delegate = context.coordinator
        textview.isEditable = true
        textview.allowsUndo = true
        textview.isRichText = true
        textview.isFieldEditor = false
        textview.isSelectable = true
        textview.usesAdaptiveColorMappingForDarkAppearance = true
        textview.drawsBackground = true
        textview.usesRuler = true
        textview.usesFindBar = true
        textview.displaysLinkToolTips = true
        textview.autoresizesSubviews = true
        textview.translatesAutoresizingMaskIntoConstraints = true
        textview.autoresizingMask = .width
        textview.usesFontPanel = true
        textview.defaultParagraphStyle = .none
        textview.usesRolloverButtonForSelection = true
        textview.font = NSFont.systemFont(ofSize: fontaize)
        textview.importsGraphics = true
        textview.allowsImageEditing = true
        textview.baseWritingDirection = .natural
        textview.insertionPointColor = NSColor(Color.accentColor)
        textview.smartInsertDeleteEnabled = true
        textview.isGrammarCheckingEnabled = true
        textview.isIncrementalSearchingEnabled = true
        textview.isAutomaticDataDetectionEnabled = true
        textview.isAutomaticLinkDetectionEnabled = true
        textview.isContinuousSpellCheckingEnabled = true
        textview.isAutomaticTextCompletionEnabled = true
        textview.isAutomaticTextReplacementEnabled = true
        textview.isAutomaticDashSubstitutionEnabled = true
        textview.isAutomaticQuoteSubstitutionEnabled = true
        textview.isAutomaticSpellingCorrectionEnabled = true
        textview.allowsCharacterPickerTouchBarItem = true
        textview.allowsDocumentBackgroundColorChange = true
        textview.textContainerInset = NSSize(width: 5, height: 5)
        textview.textContainer?.lineFragmentPadding = 5
        textview.textContainer?.lineBreakMode = .byWordWrapping
        textview.setSelectedRange(NSMakeRange(0, 0))
        textview.canDrawConcurrently = true
        textview.canDrawSubviewsIntoLayer = true
        // MARK: - ⚠️ CAUTION: DO NOT DARE TO ENABLE/UNCOMMENT OR UNLEASH THE APOCALYPSE ⚠️
        // textview.textContainer?.widthTracksTextView = true
        // textview.textContainer?.heightTracksTextView = true
        // textview.textContainer?.containerSize = scrollview.contentSize
        return scrollview
    }

    func updateNSView(_ nsView: NSScrollView, context: Context) {
        let textview = nsView.documentView as! NSTextView

        if textview.usesInspectorBar != showInspector {
            textview.usesInspectorBar = showInspector
        }

        if textview.isRulerVisible != showRuler {
            textview.isRulerVisible = showRuler
        }

        // MARK: - defaultScale not working as expected
        // nsView.animator().setMagnification(magnification, centeredAt: .zero)

        guard textview.attributedString() != attributedText else {
            return
        }
        
        guard let storage = textview.textStorage else {
            print("WARNING: Text storage is missing.")
            return
        }
        
        textview.updateRuler()
        textview.updateLayer()
        textview.updateFontPanel()
        textview.updateConstraints()
        textview.updateTrackingAreas()
        textview.updateTextTouchBarItems()
        textview.updateDragTypeRegistration()
        textview.updateQuickLookPreviewPanel()
        textview.updateTouchBarItemIdentifiers()
        textview.updateConstraintsForSubtreeIfNeeded()

        storage.setAttributedString(attributedText)
    }
    
    func onCommand(perform action: @escaping () -> Void) -> some View {
        return Image(systemName: "Circle")
    }

    class Coordinator: NSObject, NSTextViewDelegate {
        var parent: RichTextEditor
        var affectedCharRange: NSRange?
        var sharedViewModel: SharedViewModel?
        
        init(_ parent: RichTextEditor) {
            self.parent = parent
        }
        
        func textView(_ textView: NSTextView, completions words: [String], forPartialWordRange charRange: NSRange, indexOfSelectedItem index: UnsafeMutablePointer<Int>?) -> [String] {
            ["aol","2","3"]
        }
        
        func textDidReceiveInput(_ textView: NSTextView) {
            // Handle the keyboard shortcut
            textView.toggleAutomaticTextCompletion(parent)
        }
        
        func textDidChange(_ notification: Notification) {
            guard let textview = notification.object as? NSTextView else {
                return
            }
            
            self.parent.activity.send(Date.now)
            self.parent.attributedText = textview.attributedString()
        }
        
        func textView(_ textView: NSTextView, shouldChangeTextIn affectedCharRange: NSRange, replacementString: String?) -> Bool {
            return true
        }
        
        func textView(_ view: NSTextView, menu: NSMenu, for event: NSEvent, at charIndex: Int) -> NSMenu? {

            // Remove layout direction
            if let loMenu = menu.item(withTitle: "Layout Orientation") {
                menu.removeItem(loMenu)
            }

            // Add menu divider
            menu.addItem(NSMenuItem.separator())

            // Add "Show Ruler" menu item
            let showRulerItem = NSMenuItem(title: "Show Ruler", action: #selector(view.toggleRuler(_:)), keyEquivalent: "")
            showRulerItem.target = view
            menu.addItem(showRulerItem)

            // Add "Toggle Inspector Bar" menu item
            let toggleInspectorItem = NSMenuItem(title: "Use Inspector Bar", action: #selector(view.toggleInspector(_:)), keyEquivalent: "")
            toggleInspectorItem.target = view
            toggleInspectorItem.state = view.usesInspectorBar ? .on : .off
            menu.addItem(toggleInspectorItem)

            // Configure menu properties
            menu.showsStateColumn = true
            menu.autoenablesItems = true
            menu.allowsContextMenuPlugIns = true

            return menu
        }

        func textView(_ textView: NSTextView, willShow servicePicker: NSSharingServicePicker, forItems items: [Any] ) -> NSSharingServicePicker? {
            return .none
        }
    }

}

// Show Inspector
struct ShowInspectorKey: EnvironmentKey {
    static var defaultValue: Bool = false
}

// Show Ruler
struct ShowRulerKey: EnvironmentKey {
    static var defaultValue: Bool = false
}

// Font Size
struct FontSizeKey: EnvironmentKey {
    static var defaultValue: Double = 12.0
}

// Magnification
struct MagnificationKey: EnvironmentKey {
    static var defaultValue: Double = 1.0
}

// Magnification
struct FindBarPositionKey: EnvironmentKey {
    static var defaultValue: NSScrollView.FindBarPosition = .aboveContent
}

extension EnvironmentValues {
    var showRuler: Bool {
        get { self[ShowRulerKey.self] }
        set { self[ShowRulerKey.self] = newValue }
    }

    var showInspector: Bool {
        get { self[ShowInspectorKey.self] }
        set { self[ShowInspectorKey.self] = newValue }
    }

    var defaultFontSize: Double {
        get { self[FontSizeKey.self] }
        set { self[FontSizeKey.self] = newValue }
    }

    var defaultScale: Double {
        get { self[MagnificationKey.self] }
        set { self[MagnificationKey.self] = newValue }
    }

    var findBarPosition: NSScrollView.FindBarPosition {
        get { self[FindBarPositionKey.self] }
        set { self[FindBarPositionKey.self] = newValue }
    }
}

// Merged extension for View
extension View {
    func showInspector(_ value: Bool) -> some View {
        self.environment(\.showInspector, value)
    }

    func showRuler(_ value: Bool) -> some View {
        self.environment(\.showRuler, value)
    }

    func defaultFontSize(_ value: Double) -> some View {
        self.environment(\.defaultFontSize, value)
    }

    // MARK: - defaultScale not working as expected
    private func defaultScale(_ value: Double) -> some View {
        self.environment(\.defaultScale, value)
    }
    
    func findBarLocation(_ value: NSScrollView.FindBarPosition) -> some View {
        self.environment(\.findBarPosition, value)
    }
}

extension NSTextView: NSSharingServicePickerDelegate {
    public func sharingServicePicker(
        _ sharingServicePicker: NSSharingServicePicker,
        sharingServicesForItems items: [Any],
        proposedSharingServices proposedServices: [NSSharingService]
    ) -> [NSSharingService] {
        // Deactivate sharing services completely.
        return []
    }
}

extension NSTextView {
    @objc func toggleInspector(_ sender: Any) {
        withAnimation(.default){
            self.usesInspectorBar.toggle()
        }
    }
}

#Preview {
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}